Auto merge of rust-lang#116124 - WaffleLapkin:fix-proc-macro-literal-to-string, r=compiler-errors

Properly print cstr literals in `proc_macro::Literal::to_string`

Previously we printed the contents of the string, rather than the actual string literal (e.g. `the c string` instead of `c"the c string"`).

Fixes rust-lang#112820
cc rust-lang#105723

Author: bors

proc_macro/src/lib.rs

@@ -1418,7 +1418,15 @@ impl Literal {
                 let hashes = get_hashes_str(n);
                 f(&["br", hashes, "\"", symbol, "\"", hashes, suffix])
             }
-            _ => f(&[symbol, suffix]),
+            bridge::LitKind::CStr => f(&["c\"", symbol, "\"", suffix]),
+            bridge::LitKind::CStrRaw(n) => {
+                let hashes = get_hashes_str(n);
+                f(&["cr", hashes, "\"", symbol, "\"", hashes, suffix])
+            }
+
+            bridge::LitKind::Integer | bridge::LitKind::Float | bridge::LitKind::Err => {
+                f(&[symbol, suffix])
+            }
         })
     }
 }